Rf Speech Processor (Fsp); Adjusting Processor Frequency Shift - Yaesu FT-990 Operating Manual

tor the automatic control voltage, which is nega-
tive feedback in the later transmitter stages that
prevents overdriving the final amplifier (higher
ALC indicates greater reduction of drive level).
0
If this is the first time you are transmitting SSB
with the Ff-990, preset the
MIC
control to about
the 12- o'clock position, the
RF PWR
control fully
clockwise, and make sure the
VOX
is off
(A).
0 Confirm that the display shows the frequency
you want to transmit on, and make sure the
"GEN"
box is not displayed to the left of the
frequency.
0
Listen carefully on the frequency to make sure
you will not interfere with any other stations,
then press
START
to match the antenna.
0
Now press the PIT (push-to-talk) switch on
your microphone, and give your callsign (to
identify your transmission) or make your call.
You should see the meter fluctuate as you
speak.
To determine the optimum setting of the
MIC
control for your microphone, adjust it while the
RF
PWR
control is fully clockwise. Speak into the micro-
phone (at a normal level) so that the meter deflects
no further than midrange on voice peaks (the up-
per end of the blue ALC range). Once found, this
setting can be left as it is for all modes unless you
change microphones.
You can switch the
METER
selector to the
PO
posi-
tion and adjust the
RF PWR
control for more or less
output, from about 10 to 100 watts (on the second
meter scale from the top), as desired. However,
you should always use the lowest possible power
output to maintain reliable communications- not
only as a courtesy to other stations, but to mini-
mize the possibility of causing RFI and TVI, and to
maximize the life of the equipment.
Note: reducing power with the
RF PWR
control
causes the ALC voltage to increase, as can be seen
when the meter selector
is
set to the
ALC
position.
The meter will then deflect beyond the blue ALC
zone. This is normal, and is not and indication that
you should readjust the
MIC
or other controls.
RF Speech Processor (FSP)
Once the proper
MIC
control setting has been
determined (with full power), you can activate the
RF speech processor to increase the average power
of your signal. The
RF PWR
setting does not affect
speech processor adjustment or the compression
meter indication.
0
Set the
METER
selector to the
COMP
(speech proces-
sor compression) position, and press the
RF FSP
Operation
Transmitting
Adjusting Processor Frequency Shift
The unique FSP (Frequency-Shifted Proces-
sor) in the Ff-990 lets you shift the IF pass-
band (and hence the RF passband as well) of
your transmitted signal in SSB modes, to cus-
tomize your signal for your own voice char-
acteristics. LSB and USB IF offsets are set
independently.
To display the current transmitter offset for
the selected SSB mode, press and hold both
the
FAST
and
RF FSP
buttons. The FSP offset
can be set between -0.3 (-300 Hz) and 0.5
(+500Hz) by turning the tuning knob slightly
while holding the two buttons. A minus sign
indicates the offset is closer to the carrier
(low-frequency speech audio emphasized).
Of course you can adjust the offset by trial-
and-error on the air, but it is better if you have
a separate receiver in which you can hear the
effect yourself. Otherwise, we recommend
starting with + 100 Hz offset initially, to add
some "crispness" to your processed speech.
To obtain the same result on both USB and
LSB, just set them for the same offset display.
OFFSET OFFSET
+---------+
' I
t
j
LSB USB
CARRIER PASSBAND CARRIER
POINT POINT
button (at the left end of the row of buttons
along the bottom) so that its orange LED lights.
0
Now while speaking into the microphone, ad-
just the
PROC
control for a compression level of 5
to 10 dB on the
COMP
scale of the meter (the
second scale from the bottom). We do not rec-
ommend higher compression settings, as your
signal will become less readable.
0
If you want to confirm that your
MIC
control
setting is correct, set the
RF PWR
control to maxi-
mum, move the
METER
selector back to the
ALC
position, and if necessary, adjust the
MIC
control
again so that the meter stays in the blue
ALC
scale on voice peaks.
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